An FTIR study of the effects of artificial saliva on the physical characteristics of the glass ionomer cements used for art.

OBJECTIVE: To investigate the physical and chemical changes of five esthetic restorative materials in an artificial saliva using Fourier transform infrared spectroscopy (FTIR). METHODS: The materials included two glass polyalkenoate (ionomer) cements, one polyacid-modified resin composite, and two resin composites. Five fresh and 20 aged specimens for each material were immersed in 2 ml of artificial saliva at 37 degrees C for 1 week, 2 weeks, 1 month, and 2 months. They were examined by laser surface profilometer and FTIR. RESULTS: Surface roughness average (Ra) value showed significant differences among the physical properties of glass ionomers, polyacid-modified resin composite, and resin composites. SIGNIFICANCE: FTIR spectra showed that a major chemical changes in Fuji IX GP Fast glass ionomer cement in P-NH2 group bonding (900-1000 cm(-1)) that may explain the previously reported increase in microhardness after immersion. There was no direct correlation between surface roughness and spectral changes of the materials tested.     

Multiple abnormalities in a child with partial duplications of 10p and 13q from a 3:1 segregation of a maternal t(10;13) translocation.

Partial duplications of 10p and 13q in association with partial deletions of other chromosome segments have been variously reported. We describe here a female child with multiple congenital abnormalities and combined partial duplications of 10p and 13q resulting from a 3:1 segregation of a maternal t(10;13)(p13;q22). In comparing the phenotypic features of the two chromosome imbalances, the expression of features typical of partial duplication 10p appeared more pronounced.     

Pharmacokinetic properties of human fibroblast and leukocyte interferon in rabbits.

When rabbits were given intramuscular injections of the same quantities of human leukocyte or fibroblast interferons, the former produced moderately higher levels of circulating interferon. Fibroblast interferon was not cleared faster from circulation, nor was direct inactivation by rabbit blood responsible for this difference.     

Comparison of older adult subject and proxy responses on the SF-36 health-related quality of life instrument

Studies of older adults' health status and health-related quality of life (HRQoL) often rely on proxy responses when subjects have problems that affect their ability to respond. With the increased interest in outcomes research in health care, it is important to examine proxy reliability on HRQoL instruments. This study compares 32 pairs of subject-andproxy responses on the eight subscales and two summary scales of the Short Form 36 (SF-36). Subjects and their proxies, recruited from senior centers and residential facilities, were interviewed face-to-face within a seven-day period. Subjects were 60 years of age or older and had passed a brief cognitive screen, and proxies were geographically proximate and had seen the subject during the past week. Results showed that although moderate intra-class correlations were found on six of the eight measures, an item-level kappa statistic indicated poor to fair agreement on all subscales except items of Physical Functioning and Role Physical. Moreover, paired t-tests revealed proxy mean scores that were significantly lower on the Physical Functioning, Vitality, and Mental Health subscales. Given the mixed findings, until further research is done, researchers and clinicians should exercise caution when using proxy responses for older adults with the SF-36.     

Pure endoscopic resection versus laparoscopic assisted procedure for upper gastrointestinal stromal tumors: Perspective from a surgical endoscopist

Management of upper gastrointestinal (UGI) tract gastrointestinal stromal tumor (GIST) has evolved significantly over the past two decades. For GIST size smaller than 5 cm, laparoscopic resection has become the current standard. To avoid postoperative gastric deformity and preserve gastric function, laparoscopic endoscopic cooperative surgery (LECS) was developed and various modifications have been reported and utilized successfully. Pure endoscopic resection techniques have also been reported at a similar period of time, which further push the boundary of incisionless surgery in managing these lesions. Both tunneling and nontunneling exposed type endoscopic full thickness resection are well described procedures for resection of small UGI GIST. In this review, a summary of these procedures is provided, and the pros and cons of each technique from the perspective of a surgical endoscopist are discussed in detail. LECS and endoscopic resection are complementary to each other. The choice of technique should be tailored to the location, morphology, and size of the target lesions, taking into account the experience of the laparoscopic surgeons and endoscopists.     

The shufflon of Salmonella enterica serovar Typhi regulates type IVB pilus-mediated bacterial self-association

Previously, it was shown that type IVB pili encoded by the Salmonella enterica serovar Typhi pil operon are used to facilitate bacterial entry into human intestinal epithelial cells in vitro and that such entry is inhibited by purified prepilin (pre-PilS) protein (X.-L. Zhang, I. S. M. Tsui, C. M. C. Yip, A. W. Y. Fung, D. K.-H. Wong, X. Dai, Y. Yang, J. Hackett, and C. Morris, Infect. Immun. 68:3067-3073, 2000). The pil operon concludes with a simple shufflon, and a recombinase gene product (Rci) inverts DNA in the C-terminal region of the pilV gene to allow synthesis of two distinct PilV proteins, PilV1 and PilV2, which are presumptive minor pilus proteins. We show here that the type IVB pili mediate bacterial self-association, but only when the PilV1 and PilV2 proteins are not expressed. This may be achieved in wild-type serovar Typhi by rapid DNA inversion activity of the shufflon. We show that the inversion activity inhibits the expression of genes inserted between the 19-bp inverted repeats used for Rci-mediated recombination and that the activity of Rci increases when DNA is supercoiled. The data suggest that serovar Typhi self-associates under conditions (such as low oxygen tension in the gut) that favor DNA supercoiling. These results explain (i) the function of the serovar Typhi shufflon and (ii) why there are only two possible shufflon states, in contrast to the many possible states of other shufflon systems. The data further indicate that a very early step in serovar Typhi pathogenesis may be type IVB pilus-mediated self-association of bacteria in the anaerobic human small intestine prior to invasion of the human gut epithelium. The suggested type IVB pilus-dependent step in typhoid fever pathogenesis may partially explain the enhanced invasiveness of serovar Typhi for humans.